Rib extrusion



FIG. 1 is a fragmentary perspective view of a rib extrusion showing my new design;

FIG. 2 is a right-end elevational view thereof, the left-end elevational view being a mirror image thereof;

FIG. 3 is a fragmentary front elevational view thereof;

FIG. 4 is a fragmentary top plan view thereof;

FIG. 5 is a fragmentary rear elevational view thereof; and,

FIG. 6 is a fragmentary bottom plan view thereof. 

The ornamental design for a rib extrusion, as shown and described. 